Well servicing apparatus and method

ABSTRACT

A well servicing apparatus and method which facilitates servicing of a well without removal of the wellhead equipment, production tubing, or pump drive rod. One embodiment of the invention allows flexible tubing to be inserted into the production tubing string of a well. Fluid can then be pumped through the flexible tubing for purposes such as removing sand from the production tubing string. Another embodiment of the invention allows flexible tubing to be inserted into either the production tubing string or well casing or both. Fluid can then be pumped through the flexible tubing for purposes such as removing sand from either the production tubing string or well casing.

FIELD OF THE INVENTION

[0001] The present invention relates to apparatus and methods for servicing wells, particularly for servicing oil wells to remove sand.

BACKGROUND OF THE INVENTION

[0002] In the production of a fluid such as hydrocarbons from a subsurface reservoir, a well is drilled down to provide a path for the fluid to flow to the surface. A well casing is used to keep the earth from collapsing the well. The casing is then perforated at a desired depth to allow the reservoir fluid (such as oil) to flow into the casing. A tubing string, extending from the surface to the bottom of the well, is provided for carrying the fluid to the surface. If the formation pressure is sufficiently high, the reservoir fluid flows naturally to the surface. However, when there is not sufficient pressure, lift must be provided, commonly by the use of downhole pumps. Such pumps may be operated from the surface by either a rotating or reciprocating drive rod.

[0003] With many producing wells, the incursion of sand is a problem. Sand may accumulate in the casing or in the production tubing. When it becomes apparent that the incursion of sand is adversely affecting the production from the well to such an extent that the well is not economical, the well needs to be serviced to clean out the accumulated sand. Traditional procedures for removing sand from a well involve removing the casing spool or tubing spool from the wellhead and the use of a service rig to pull out the tubing string and drive rod. A sand line bailing unit or tubing bailing unit is then used to remove sand from the casing or the production tubing string. This is a costly and time-consuming procedure, and the opening of the well to the atmosphere can result in release of the reservoir fluids and gases, which can harm the environment and endanger those near the well. In addition, the open well can become contaminated or damaged by such items as wrenches, tools, dirt or bolts.

[0004] U.S. Pat. No. 6,315,046 (Jack et al), which corresponds to Canadian Patent No. 2,268,223 describes a method and apparatus which provides for simplified and rigless servicing of a well casing. The apparatus includes a casing spool that allows flexible tubing to be inserted into the casing without removing the apparatus, tubing or drive rod. The flexible tubing can be extended down the well into the annular space between the production tubing string and the casing, and fluid can then be pumped through the flexible tubing to flush out sand in the well.

[0005] Canadian Patent Application No. 2,310,236 (Komistek) describes a tubing clean-out spool having an entry port allowing flexible tubing to be inserted into the annular space between the production tubing and drive rod. A disadvantage of the Komistek apparatus is that due to the frictional contact between the flexible tubing and the tubing spool, both the tubing spool and the flexible tubing may be subject to rapid wear which could necessitate frequent replacement of the tubing spool, plus associated costs and lost well production.

[0006] Accordingly, there is a need for well servicing apparatus and method which facilitate servicing and flushing of the annular space between the drive rod and the production tubing, without being prone to frequent and expensive replacement of components, and without requiring removal or disassembly. In addition, there is a need for such well servicing apparatus and method which also facilitate servicing and flushing of the annular space between the production tubing and the well casing without requiring removal or disassembly. The present invention is directed to these needs.

BRIEF SUMMARY OF THE INVENTION

[0007] In general terms, the present invention relates to an improved well servicing apparatus and method utilizing a housing which includes a passage that allow flexible tubing to be inserted into the production tubing string in a helical orientation without the removal of the apparatus or the drive rod from the well. The present invention also relates to an improved well servicing apparatus and method utilizing a housing which includes passages that allow flexible tubing to be inserted into the well casing in a helical orientation without the removal of the apparatus or the production tubing.

[0008] Accordingly, in one aspect, the invention is a well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having:

[0009] (a) a primary passage extending through the housing from the lower end to the upper end; and

[0010] (b) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage;

[0011] wherein a drive rod may be disposed longitudinally through the primary passage.

[0012] Preferably the well servicing apparatus further comprises a guide tube which may be detachably connected to the housing in association with the production tubing access passage. The well servicing apparatus may further comprise a flange attached to the housing near its upper end, said flange having an opening for supporting the guide tube.

[0013] In the preferred embodiment, the exterior surface of the housing defines a shoulder, and the production tubing access passage extends from the primary passage to the exterior surface on the shoulder.

[0014] In another aspect, the invention is a well servicing apparatus comprising:

[0015] (a) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having:

[0016] (i) an upper primary passage extending through the upper housing from the lower end to the upper end; and

[0017] (ii) a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;

[0018] (b) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having:

[0019] (i) a lower primary passage extending through the lower housing from the lower end to the upper end;

[0020] (ii) a casing access passage extending generally upward from the lower primary passage to the exterior surface;

[0021] (c) tubing string suspension means, for supporting a production tubing string; wherein:

[0022] (d) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and

[0023] (e) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string.

[0024] Preferably, at least a portion of the casing access passage has a helical orientation relative to the longitudinal axis of the lower primary passage. Ancillary wellhead components may be interposed between the upper housing and lower housing.

[0025] Preferably, the well servicing apparatus further comprises a guide tube which may be detachably connected to the upper housing in association with the production tubing access passage. More preferably, the well servicing apparatus further comprises a flange attached to the upper housing near its upper end, said flange having an opening for supporting the guide tube.

[0026] In the preferred embodiment, the exterior surface of the upper housing defines a shoulder, and the production tubing access passage extends from the upper primary passage to the exterior surface on the shoulder.

[0027] Preferably, the well servicing apparatus further comprises a guide tube which may be detachably connected to the lower housing in association with the casing access passage.

[0028] In the preferred embodiment, the exterior surface of the lower housing defines a shoulder, and the casing access passage extends from the lower primary passage to the exterior surface on the shoulder.

[0029] Preferably, the tubing string suspension means is a bowl for a tubing hanger.

[0030] In a further aspect, the invention is a method of servicing a well, comprising the steps of:

[0031] (a) providing a well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having:

[0032] (i) a primary passage extending through the housing from the lower end to the upper end, through which said primary passage a drive rod may be longitudinally disposed; and

[0033] (ii) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage;

[0034] (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;

[0035] (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and

[0036] (d) pumping a selected fluid through the flexible tubing.

[0037] In another aspect, the invention is a method of servicing a well, comprising the steps of:

[0038] (a) providing a well servicing apparatus comprising:

[0039] (i) an upper housing having an upper end, a lower end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;

[0040] (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end, and a casing access passage extending generally upward from the lower primary passage to the exterior surface;

[0041] (iii) tubing string suspension means, for supporting a production tubing string; wherein:

[0042] (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and

[0043] (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string;

[0044] (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;

[0045] (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and

[0046] (d) pumping a selected fluid through the flexible tubing.

[0047] In another aspect, the invention is a method of servicing a well, comprising the steps of:

[0048] (a) providing a well servicing apparatus comprising:

[0049] (i) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;

[0050] (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end; and a casing access passage extending generally upward from the lower primary passage to the exterior surface;

[0051] (iii) tubing string suspension means, for supporting a production tubing string; wherein:

[0052] (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and

[0053] (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string;

[0054] (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;

[0055] (c) passing flexible tubing through the casing access passage, such that the flexible tubing enters the annular space between the production tubing string and the well casing; and

[0056] (d) pumping a selected fluid through the flexible tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Embodiments of the invention will now be described with reference to the accompanying figures, in which numerical references denote like parts, and in which:

[0058]FIG. 1 is a sectional view of a first embodiment of the invention, shown with flexible tubing passing through the guide tube into the production string.

[0059]FIG. 2 is a sectional view of the first embodiment of the invention, shown with the guide tube removed and a closure sealing the production tubing access passage.

[0060]FIG. 3 is a side view, in partial cutaway section, of a second embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0061] Referring to FIGS. 1 and 2, the apparatus of the present invention, in one embodiment, generally represented by reference numeral 10, includes a housing 12 that has a lower end 16, an upper end 14, and an exterior surface 18.

[0062] A primary passage 24 extends through housing 12 from the lower end 16 to the upper end 14. A production tubing access passage 36 extends generally upward from primary passage 24 to the exterior surface 18 at an angle towards the upper end 14 such that at least a portion of production tubing access passage 36 has a helical orientation relative to the longitudinal axis of primary passage 24. A drive rod 26 may be disposed longitudinally through primary passage 24.

[0063] In the preferred embodiment, the exterior surface 18 defines a shoulder 20 protruding from the general outline of the housing 12, and the production tubing access passage 36 extends from the primary passage 24 to the exterior surface 18 on the shoulder 20. In the preferred embodiment, a guide tube 42 can be detachably connected to the housing 12 in association with the production tubing access passage 36. Guide tube 42 may be supported at by a flange 44 positioned on housing 12 toward upper end 14. Flexible tubing 38 may be inserted into production tubing access passage 36.

[0064] Flange 48 is provided at lower end 16 of housing 12 for the purpose of mounting well servicing apparatus 10. Packing 30 may be used to seal the opening between rod 26 and housing 12 near the upper end 14 of housing 12. Packing 30 is retained in place by packing retainer 32.

[0065] Referring to FIG. 2, a closure 40 closes production tubing access passage 36 when production tubing access passage 36 is not in use. To place closure 40 on production tubing access passage 36, guide tube 42 (FIG. 1) must be detached.

[0066] In an alternative embodiment of the invention, illustrated in FIG. 3, there is provided a well servicing apparatus 100, which includes an upper housing 112 and a lower housing 162.

[0067] Upper housing 112 has a lower end 116, an upper end 114, and an exterior surface 118. An upper primary passage 124 extends through upper housing 112 from lower end 116 to upper end 114. A production tubing access passage 136 extends generally upwards from upper primary passage 124 to the exterior surface 118 at an angle towards upper end 114, wherein at least a portion of production tubing access passage 136 has a helical orientation relative to the longitudinal access of upper primary passage 124.

[0068] In the preferred embodiment, the exterior surface 118 defines a shoulder 120 protruding from the general outline of the upper housing 112, and the production tubing access passage 136 extends from the upper primary passage 124 to the exterior surface 118 on the shoulder 120. In the preferred embodiment, a guide tube 142 can be detachably connected to the upper housing 112 in association with the production tubing access passage 136. Guide tube 142 may be supported by flange 144 positioned on housing 112 toward upper end 114.

[0069] Flange 148 is provided at lower end 116 of housing 112 for the purpose of mounting the upper housing 112 of well servicing apparatus 100. Packing (not shown) may be used to seal the opening between rod 26 and upper housing 112 near the upper end 114 of housing 112. Packing (not shown) similar to packing 30 (FIGS. 1 and 2) is retained in place by packing retainer (not shown) similar to packing retainer 32 (FIGS. 1 and 2).

[0070] The lower housing 162 has a lower end 166, and upper end 164, and an exterior surface 168. A lower primary passage 172 extends through the lower housing 162 from the lower end 166 to the upper end 164. A casing access passage 174 extends generally upward from the lower primary passage 172 to the exterior surface 168. In the preferred embodiment, at least a portion of casing access passage 174 has a helical orientation relative to the longitudinal access of the lower primary passage 172 of lower housing 162.

[0071] In the preferred embodiment, the exterior surface 168 defines a shoulder 170 protruding from the general outline of the lower housing 162, and the casing access passage 174 extends from the lower primary passage 172 to the exterior surface 168 on the shoulder 170. In the preferred embodiment, a guide tube 176 can be detachably connected to the lower housing 162 in association with the casing access passage 174.

[0072] Flange 178 is provided at upper end 164 of lower housing 162, and flange 182 is provided at the lower end 166 of lower housing 162, for the purpose of mounting lower housing 162 of well servicing apparatus 100.

[0073] The upper housing 112 is connected to the lower housing 162 such that upper primary passage 124 and lower primary passage 172 are substantially coaxial. The connection may be direct, or ancillary wellhead components 180 may be interposed between the upper housing 112 and the lower housing 162. A drive rod 26 may be disposed longitudinally through the upper primary passage 124 and lower primary passage 172 and into the bore of the production tubing string 156.

[0074] Tubing string suspension means (not shown) is provided for supporting production tubing string 156. In the preferred embodiment, a bowl (not shown) for a tubing hanger (not shown) is provided as the tubing suspension means.

[0075] A closure (not shown) similar to closure 40 (FIG. 2) may be used to close production tubing access passage 136 and casing access passage 174 when the well servicing apparatus 100 is not in use.

[0076] With reference to FIGS. 1 and 2, the use and operation of the well servicing apparatus generally identified by reference numeral 10 will now be described.

[0077] Referring to FIG. 1, the well servicing apparatus 10, as described above, has been developed to facilitate the servicing of a well with flexible tubing 38. Production tubing access passage 36 allows for flexible tubing 38 to be passed through production tubing access passage 36 into primary passage 24 and into the production tubing string (not shown) without removing well servicing apparatus 10 or drive rod 26 from primary passage 24 of well servicing apparatus 10. The helical orientation of the production tubing access passage 36 facilitates introduction of the flexible tubing 38, thereby reducing abrasion and wear of the flexible tubing 38 and the internal walls of the production tubing access passage 36. Detachable guide tube 42 may be attached to production tubing access passage 36 for the purpose of guiding flexible tubing 38 into production tubing access passage 36. A selected fluid, for example water, is then pumped through flexible tubing 38.

[0078] When production tubing access passage 36 is not in use, closure 40 may be used to close production tubing access passage 36.

[0079] With reference to FIG. 3, the use and operation of the well servicing apparatus generally identified by reference numeral 100 will now be described.

[0080] Referring to FIG. 3, the well servicing apparatus 100, as described above, has been developed to facilitate the servicing of a well with flexible tubing 38. Production tubing access passage 136 allows for flexible tubing 38 to be inserted through production tubing access passage 136 into upper primary passage 124 to a desired depth within the well without removing well servicing apparatus 100, production tubing string 156, or drive rod 26. The helical orientation of the production tubing access passage 136 facilitates introduction of the flexible tubing 38, thereby reducing abrasion and wear of the flexible tubing 38 and the internal walls of the production tubing access passage 136. Guide tube 142 may be attached to production tubing access passage 136 for the purpose of guiding flexible tubing 38 into production tubing access passage 136. A selected fluid, for example water, is then pumped through the flexible tubing 38.

[0081] Casing access passage 174 allows for flexible tubing 38 to be inserted through casing access passage 174 into casing 60 to a selected depth within the well without removing well servicing apparatus 100, tubing string suspension means (not shown), production tubing string 156, or drive rod 26. A selected fluid, for example water, is then pumped through the flexible tubing 38.

[0082] In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following that word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element.

[0083] It will be readily seen by those skilled in the art that various modifications of the present invention may be devised without departing from the essential concept of the invention, and all such modifications are intended to be included in the scope of the claims appended hereto. 

What is claimed is:
 1. A well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having: (a) a primary passage extending through the housing from the lower end to the upper end; and (b) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage; wherein a drive rod may be disposed longitudinally through the primary passage.
 2. The apparatus of claim 1, further comprising a guide tube which may be detachably connected to the housing in association with the production tubing access passage.
 3. The apparatus of claim 2, further comprising a flange attached to the housing near its upper end, said flange having an opening for supporting the guide tube.
 4. The apparatus of claim 1, wherein the exterior surface of the housing defines a shoulder, and wherein the production tubing access passage extends from the primary passage to the exterior surface on the shoulder.
 5. A well servicing apparatus comprising: (a) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having: (i) an upper primary passage extending through the upper housing from the lower end to the upper end; and (ii) a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage; (b) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having: (i) a lower primary passage extending through the lower housing from the lower end to the upper end; and (ii) a casing access passage extending generally upward from the lower primary passage to the exterior surface; and (c) tubing string suspension means, for supporting a production tubing string; wherein: (d) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and (e) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string.
 6. The apparatus of claim 5, wherein at least a portion of the casing access passage has a helical orientation relative to the longitudinal axis of the lower primary passage.
 7. The apparatus of claim 5, wherein one or more ancillary wellhead components are interposed between the upper housing and lower housing.
 8. The apparatus of claim 5, further comprising a guide tube which may be detachably connected to the upper housing in association with the production tubing access passage.
 9. The apparatus of claim 8, further comprising a flange attached to the upper housing near its upper end, said flange having an opening for supporting the guide tube.
 10. The apparatus of claim 5, wherein the exterior surface of the upper housing defines a shoulder, and wherein the production tubing access passage extends from the upper primary passage to the exterior surface on the shoulder.
 11. The apparatus of claim 5, further comprising a guide tube which may be detachably connected to the lower housing in association with the casing access passage.
 12. The apparatus of claim 5, wherein the exterior surface of the lower housing defines a shoulder, and wherein the casing access passage extends from the lower primary passage to the exterior surface on the shoulder.
 13. The apparatus of claim 5, wherein the tubing string suspension means is a bowl for a tubing hanger.
 14. A method of servicing a well, comprising the steps of: (a) providing a well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having: (i) a primary passage extending through the housing from the lower end to the upper end and, through which said primary passage a drive rod may be longitudinally disposed; (ii) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage; (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing; (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and (d) pumping a selected fluid through the flexible tubing.
 15. A method of servicing a well, comprising the steps of: (a) providing a well servicing apparatus comprising: (i) an upper housing having an upper end, a lower end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage; (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end, and a casing access passage extending generally upward from the lower primary passage to the exterior surface; (iii) tubing string suspension means, for supporting a production tubing string; wherein: (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string; (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing; (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and (d) pumping a selected fluid through the flexible tubing.
 16. A method of servicing a well, comprising the steps of: (a) providing a well servicing apparatus comprising: (i) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage; (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end, and a casing access passage extending generally upward from the lower primary passage to the exterior surface; (iii) tubing string suspension means, for supporting a production tubing string; wherein: (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string; (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing; (c) passing flexible tubing through the casing access passage, such that the flexible tubing enters the annular space between the production tubing string and the well casing; and (d) pumping a selected fluid through the flexible tubing. 